Comprehensive circRNA-microRNA-mRNA network analysis revealed the novel regulatory mechanism of Trichosporon asahii infection.

BACKGROUND: Invasive Trichosporon asahii (T. asahii) infection frequently occurs with a high mortality in immunodeficient hosts, but the pathogenesis of T. asahii infection remains elusive. Circular RNAs (circRNAs) are a type of endogenous noncoding RNA that participate in various disease processes. However, the mechanism of circRNAs in T. asahii infection remains completely unknown. METHODS: RNA sequencing (RNA-seq) was performed to analyze the expression profiles of circRNAs, microRNAs (miRNAs), and mRNAs in THP-1 cells infected with T. asahii or uninfected samples. Some of the RNA-seq results were verified by RT-qPCR. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to analyze the differentially expressed mRNAs. A circRNA-miRNA-mRNA network was constructed and verified by dual-luciferase reporter assay and overexpression experiments. RESULTS: A total of 46 circRNAs, 412 mRNAs and 47 miRNAs were differentially expressed at 12 h after T. asahii infection. GO and KEGG analyses showed that the differentially expressed mRNAs were primarily linked to the leukocyte migration involved in the inflammatory response, the Toll-like receptor signaling pathway, and the TNF signaling pathway. A competing endogenous RNA (ceRNA) network was constructed with 5 differentially expressed circRNAs, 5 differentially expressed miRNAs and 42 differentially expressed mRNAs. Among them, hsa_circ_0065336 was found to indirectly regulate PTPN11 expression by sponging miR-505-3p. CONCLUSIONS: These data revealed a comprehensive circRNA-associated ceRNA network during T. asahii infection, thus providing new insights into the pathogenesis of the T. asahii-host interactions.

Environmental investigations and molecular typing of Aspergillus in a Chinese hospital.

Invasive fungal infections due to Aspergillus species have become a major cause of morbidity and mortality among immunocompromised patients. In order to determine the possible relationship between environmental contamination by Aspergillus and the occurrence of invasive aspergillosis, a 1-year prospective study was carried out in a tertiary hospital in China. Air, surface, and tap water sampling was performed twice monthly at the bone marrow transplant (BMT) department, intensive care unit (ICU), neurosurgery intensive care unit (NICU), and outdoors. Nose, pharynx, and sputum samples were collected from high-risk patients. Isolates of Aspergillus from the environment and patients were genotyped by random amplification of polymorphic DNA (RAPD) assay to investigate the origin of infection. Mean total Aspergillus count was 7.73, 8.94, 13.19, and 17.32 cfu/m(3) in the BMT department, ICU, NICU, and outdoors, respectively. RAPD analysis by R108 primer demonstrated that strains isolated from patients in NICU were identical to the environmental strain. Strains isolated from patients in ICU differed from the environmental strain. Aspergillus contamination was found in the BTM department, NICU, and ICU. Clinical and environmental strains from NICU had identical genotypes. These findings suggest that Aspergillus is found in the hospital environment including the air, surface, and tap water. The genotypes of Aspergillus were identical from patients and the environment, suggesting that clinical infection may originate from the hospital environment.

ATF3 activates Stat3 phosphorylation through inhibition of p53 expression in skin cancer cells.

AIM: ATF3, a member of the ATF/CREB family of transcription factors, has been found to be selectively induced by calcineurin/NFAT inhibition and to enhance keratinocyte tumor formation, although the precise role of ATF3 in human skin cancer and possible mechanisms remain unknown. METHODS: In this study, clinical analysis of 30 skin cancer patients and 30 normal donors revealed that ATF3 was accumulated in skin cancer tissues. Functional assays demonstrated that ATF3 significantly promoted skin cancer cell proliferation. RESULTS: Mechanically, ATF3 activated Stat3 phosphorylation in skin cancer cell through regulation of p53 expression. Moreover, the promotion effect of ATF3 on skin cancer cell proliferation was dependent on the p53-Stat3 signaling cascade. CONCLUSION: Together, the results indicate that ATF3 might promote skin cancer cell proliferation and enhance skin keratinocyte tumor development through inhibiting p53 expression and then activating Stat3 phosphorylation.

Breakthrough trichosporonosis in patients receiving echinocandins: case report and literature review.

Trichosporon species now ranks as the second most common cause of disseminated yeast infections with a high mortality rate. Breakthrough trichosporonosis in patients receiving echinocandins therapy is being recognized recently. We present a case of breakthrough trichosporonosis with acute viral myocarditis while receiving caspofungin therapy. Trichosporon infection should be considered in patients, who have risk factors for invasive fungal infection and develop unexplained clinical manifestations of infection despite treatment with echinocandins.

Environment surveillance of filamentous fungi in two tertiary care hospitals in China.

BACKGROUND: Invasive fungal infections have constituted an increasingly important cause of morbidity and mortality in immunocompromised patients. In this study, a surveillance project was conducted in three different intensive care units of two large tertiary hospitals in China. METHODS: A one-year surveillance project was conducted in two tertiary hospitals which located in northern China and southwest China respectively. Air, surfaces and tap water were sampled twice a month in a central intensive care unit, a bone marrow transplant unit, a neurosurgery intensive care unit and a live transplant department. Environmental conditions such as humidity, temperature and events taking place, for example the present of the visitors, healthcare staff and cleaning crew were also recorded at the time of sampling. RESULTS: The air fungal load was 91.94 cfu/m(3) and 71.02 cfu/m(3) in the southwest China hospital and the northern China hospital respectively. The five most prevalent fungi collected from air and surfaces were Penicillium spp., Cladospcrium spp., Alternaria spp., Aspergillus spp. and Saccharomyces spp. in the southwest China hospital, meanwhile Penicillium spp., Fusarium spp., Aspergillus spp., Alternaria spp. and Cladospcrium spp. in the northern China hospital. The least contaminated department was intensive care units, and the heaviest contaminated department was neurosurgery intensive care unit. Seventy-three percent of all surfaces examined in the northern China hospital and eighty-six percent in the southwest China hospital yielded fungi. Fifty-four percent of water samples from the northern China hospital and forty-nine percent from the southwest China hospital yielded fungi. CONCLUSIONS: These findings suggested that the fungus exist in the environment of the hospital including air, surface and water. Air and surface fungal load fluctuated over the year. Air fungal load was lower in winter and higher in summer and autumn, but seldom exceeded acceptable level. The higher values were created during May to August in the northern China hospital and May to June and September to October in the southwest China hospital. A correlation between air fungal load and humidity, as well as personnel was observed.

Uncommon characteristics of the structure and development of Trichosporon asahii.

BACKGROUND: Trichosporon asahii (T. asahii) is one of the most important pathogenic fungus in the genus of trichosporon. Although the species identification of T. asahii was based upon the complicated results of morphologic, biochemical and biologic examination, the morphology characteristic is still the first clue to the species. Some common structures of T. asahii had been described such as arthrofilaments and arthroconidia, but other important structures of T. asahii were unclear. METHODS: Six strains of T. asahii were incubated on the slant and micro culture of Sabouraud's dextrose agar at 30 degrees C for 7 days. Samples were fixed using 2% paraformaldehyde and 2.5% glutaraldehyde. T. asahii was observed under scanning electron microscope and transmission electron microscope. RESULTS: The detailed characteristics of the diverse sites of germination, as well as some uncommon structures such as giant cell, sarcinate, and club-shaped macroconidia, were presented. The pseudohyphae of T. asahii were noted to produce true hyphae, either along the longitude axis or on the flank. T. asahii was noted to have blastic and thallic conidiation. Digitated branches, trichoid structures and septa inside the spores were detected. CONCLUSION: These results may add our knowledge to the structure and development of T. asahii.

[Effects of HS1-associated protein X-1 on the lupus activities: experiment with MRL/lpr lupus-like mice].

OBJECTIVE: To investigate the effects of HS1-associated protein X-1 (HAX-1) on the lupus activity of MRL/lpr lupus-like mice. METHODS: Fifteen MRL/lpr mice were divided into 3 equal groups: Group A, injected with phosphate-buffered saline, Group B, injected intraperitoneally with control virus AdEGFP and Group C, injected intraperitoneally with recombinant AdHAX-1 twice a week for 4 weeks. Peripheral blood samples were collected before the injection, and 2 and 4 weeks after the injection to be detected the white blood cell count, antinuclear antibody (ANA), anti-double strand-DNA antibodies, circulating immune complex (CIC), anti-histone antibodies, and interferon (IFN)-gamma. The level of urine protein was measured, too. Then the mice were killed, a kidney underwent direct immunofluorescence (DIF) to observe the deposition of Immune complexes, and the other kidney underwent periodic acid-Schiff (PAS) staining and pathological examination. MTT method was used to detect the proliferation of the lymphocytes in the spleen. Splenocytes were isolated from the other 15 MRL/lpr mice and then divided into 4 groups: Group, transfected with DMRIE-C without plasmid; Group E, as negative control group; Group F, transfected with blank plasmid pGenesil-1; and Group G, transfected with pGenesil-HAX-1. Forty-eight hours later MTT method was used to detect the proliferation rateof the spleen lymphocytes. RESULTS: The urine protein level of Group C was significantly higher than those of Groups A and B (both P < 0.01). Four weeks later the levels of ANA, anti-double strand DNA antibodies, and IFN-gamma were all significantly higher than those of Groups A and B (all P < 0.01). Hypercellularity and increased deposition of IgG in glomeruli were also observed in Group C. The score of glomeruli lesion of Group C (1.50 +/- 0.34) was significantly higher than those of Groups A (0.67 +/- 0.14) and Groups B (0.81 +/- 0.26) (both P < 0.01). MTT method showed that the growth curve of the spleen lymphocytes of Group C was higher than those of Groups A and B. The spleen lymphocyte proliferation rate and the levels of IFN-gamma of Group G was significantly lower than that of Group F (both P < 0.05). CONCLUSION: One of the important factors in apoptosis regulation of SLE, HAX-1 may be involved in the pathogenesis of SLE, and the silence of HAX-1 may be beneficial for the improvement of SLE.

Pathogenicity of Trichosporon asahii in a murine model of disseminated trichosporonosis.

BACKGROUND: In recent years, superficial and deep mycoses caused by trichosporon were occasionally reported. In 2001, we reported the first case of disseminated trichosporonosis caused by Trichosporon asahii (T. asahii) in China. In this study, the pathogenicity of T. asahii was investigated in a murine model of disseminated trichosporonosis. METHODS: Seventy-five mice were randomly divided into 7 groups. Each group was inoculated with T. asahii, through intradermal, gastrointestinal tract or intravenous injection. The mice in the experimental groups were given an intraperitoneal injection of cyclophosphamide (CY) to induce granulocytopenia. Mice in the therapeutic group were given both liposomal amphotericin B and fluconazole. The main viscera of the mice were examined by means of tissue culture and pathologic sections. RESULTS: In the two intravenous inoculation groups, T. asahii was isolated from at least one organ in 10 of the 12 granulocytopenic mice and 2 of the 14 immunocompetent mice. Two of the 7 mice in the granulocytopenia group presented with lesions in the inoculation position, but none of the 30 mice in the granulocytopenia and the control group which were inoculated intradermally or through the gastrointestinal tract had viscera infection. In the therapeutic group, the ratio of consequently dead mice, the number of involved viscera, and the incidence of systemic infection were significantly less than the untreated group. Acute purulent inflammation and granulomatous inflammation were the main pathological changes in the course of the infection. Arthrospores and filaments were found in the focus. CONCLUSIONS: T. asahii is an opportunistic pathogen that causes cutaneous and visceral infections in immunologically impaired hosts. An immunocompetent host was to be infected by the invading T. asahii. Several organs, namely the liver, lungs, kidneys, spleen and heart, were predisposed. The therapy of combining liposomal amphotericin B with fluconazole can prevent the host from an infection and inhibit the diffusion of the infection.

[Significance of IGS1, ITS and D1/D2 regions in molecular identification of Trichosporon species and genotype of T. asahii in China].

OBJECTIVE: To compare the sensitivity and specificity in molecular identification in different DNA regions of Trichosporon species and to study the genotype of T. asahii isolated from clinical specimens in China. METHODS: DNA was extracted from the cells of all experimental strains by using a method of glass bead method. The D1/D2, ITS and IGS1 regions were amplified by PCR with specific primers, the PCR products were cloned and sequenced. The sequences were referred to GenBank and compared with the other sequences of the Trichosporon species from GenBank by the software CLUSTAL X 1.83. Phylogenetic trees were constructed and genotypes were determined. RESULTS: The D1/D2 regions in T. asahii (CBS2479), T. dermatis, and T. laibachii were 640, 639, and 637 bp in length respectively, the ITS regions were 541, 528, and 531 bp respectively in length, and the IGS1 regions were 643, 515, and 411 bp respectively. The sequence similarity of the D1/D2 region was 89% - 99%, that of ITS and IGS1 regions were 85% - 99% and 11% - 95% respectively. The clinically isolated strains BZP07001, BZP07002, BZP07004, and BZP07005 belonged to genotype I, and the strain BZP07003 to genotype IV. CONCLUSION: The sensitivity and specificity of the IGS1 region was higher than those of the D1/D2 and ITS regions in identification of phylogenetically closely related Trichosporon species. T. asahii isolated from clinical specimens in China belongs to either genotype I or genotype IV.